Safety valve



Aug. 29, 1933. c. E. LUCKE SAFETY VALVE Filed Dec. 2, 1930 MI ENTQR BYJaw ATTORNEY Patented Aug. 29, 1933 1,924,563 I SAFETY VALVE Charles E.Lucke, New

The Babcock &

York, N. Y., assignor to Wilcox Company, Bayonne,

N. 1., a corporation of New Jersey Application December 2', 1930. SerialNo. 499,493

7 Claims.

This invention relates to safety valves that are especially useful inconnection with steam boilers in which superheated steam is generated.In boilers of this type there is necessarily a drop in steam pressurebetween the saturated steam space of the boiler and the outlet of thesuperheater due to the friction of the steam as it passes fromthe steamand water drum through connections and superheater on the way to thesteam main.

In installations that are provided with a safety valve for the saturatedsteam and also a safety valve for the superheated steam, the saturatedsteam valve would always'open prior to the superheated steam valveduring operation of the boiler if they were set at the same pressure.Should this happen the steam would flow from the steam and water drumthrough the saturated steam safety valve and the flow through thesuperheater would be diminished until, in the extreme case, it wouldstop, and the steam in the superheater tubes would be stagnant, and thiswould result in the burning out of the superheater tubes. In order toprevent the danger of the flow of steam to the superheater diminishingor entirely stopping when the saturated steam valve blows, thesuperheated steam valve is set to blow at a pressure somewhat lower thanthat corresponding to the saturated steam operating pressure afterallowing for the drop in pressure' due to friction, with the result thatsince the operating pressure is that of the saturated steam, the maximumpressure of the steam that is being deliven :l to the main is therebycaused to be less since it is governed by the superheated steam safetyvalve. By the present invention the superheated steam valve can'be setto blow at the same pressure as the saturated steam valve, and, whileeliminating the danger of the latter blowing before the former,diminishing the to be delivered from the boiler with safety than waspossible in prior installations.

The invention will be understood from the description in connection withthe accompanyingdrawing in which Fig. 1 is a side elevation of anillustrative embodiment of the invention and Figs. 2 and 3 are sectionson an enlarged scale supply of steam to the superheater,- it alsoenables higher pressure superheated steam set to open at apre-determined sure.

Reference the superheater of aspring 4' for setting pre-determined steampressure.

A waste steam pipe 5 leads aw saturated steam valve 2. A venturi steampresay from the 6 is provided in the pipe 5. A pipe '7 leads from thethroat of the venturi 6 to the inside of a siphon bellows 8. A pipe 9leads from the entrance of the venturi to a cylinder 10 in which thesiphon 8 is located so that the siphon will be contr'acted by thedifference in pressure on the inside and outside thereof due to thesteam flowing out of the safety 'valve 2 and venturi 6 to the wastesteam pipe A piston rod 11 through the stufling boxes 12 and 1 throughthe 5.

extends from the siphon 8 3 to the piston 14 that is fitted in thecylinder 15. A pipe 16 leads from the cylinder 15 to the lower end of anopen ended cylinder 17 beneath a piston 18 in the cylinder. The piston18 is 0 means of the piston rc onnected by d 19 to the valve disc of thesuperheated steam safety valve 4 so that upward movement of the piston18 will open this valve. A vent 20 is provided for the pipe 16.

A pipe 21 the valve 4. A heater outlet 3 for connection toa A pipe 23with branches 24 and the cylinder 15 on opposite leads the waste steamaway from flange 22 is provided on the supersteam main. 24 leads tosides of the piston 14 and is supplied with a fluid under pressure, suchas steam from the drum 1, for example, although other fluids underpressure could be employed to equally good advantage.

In. the modification shown in Fig.

terminates in a bent 2 the pipe '1 end near the throat of the venturi 6so that a difference in pressure between the pipes 7 and 9 is created bythe flow of'steam through the venturi 6.

' In the modification shown in Fig. ence in pressure between obtained bymeans of a restricted 3 the differthe pipes '7 and 9 is orificecomprising an orifice plate 25 with an orifice 26 through it withconically shaped connections 2'7 extending from the inside of the pipe 5tothe orifice 26 on opposite sides of the plate 25. The

through the orifice 26 causes a differ sure in the pipes 7 and 9.

The operation is as follows: As soon as the saturated ste or opens, thedifference in pressur flow of waste steam from the valve 2 passing encein presam valve 2 blows e created in the pipes 7 and 9 connected to theventuri 6 causes the siphon 8 to contract and move the piston 14, thuspermitting the fluid under pressure that enters the cylinder 15 from thepipe 23 to flow through the pipe 16 and lift the piston 18 in thecylinder 17, thus promptly opening the valve4, even though the steampressure in the outlet 3 is not sufficient to open this valve. In thisway the flow of steam through the superheater is maintained, thusavoiding the danger of the superheater being burned out.

As soon as steam ceases to flow through the outlet 5 from the valve 2the equalized pressures in the pipes ,7 and 9 will permit the siphon 8to extend to its normal length and move the piston 14 to close theentrance to the pipe 16, whereupon the fluid in the pipe 16 and underthe 'piston 18 in the cylinder 17 will escape through the vent 20, thuspermitting the valve 4 to close promptly after the valve 2 closes.However, the vent 20 is not large enough to permit escape of fluidsufficiently rapidly to prevent the piston 18 from opening the valve 4when the valve 2' opens.

I claim:

1. In a boiler, a safety valve for saturated steam, a safety valve forsuperheated steam, and means to cause the latter valve to open byopening the former, said means comprising a diiferential pressurecreating device in the outlet from saidsaturated steam valve.

2. In a boiler,a safety valve for saturated steam, a safety valve forsuperheated steam, a pressure differential device connected to theoutlet from said saturated steam valve, and means operated by saidpressure differential device for opening said superheated steam valve.

' 3. In a boiler, a safety valve for saturated steam, a safety valve forsuperheated steam, a

Patent No. l, 924, 563.

cylinder, a piston in said cylinder operated by escape of steam fromsaid saturated steam valve, a. second cylinder, a piston in said secondcylinder connected to said superheated steam valve, and a pipeconnecting said cylinders.

4. In a boiler, a safety valve for saturated steam, a safety valve forsuperheated steam, a cylinder, a piston in said'cylinder operated byescape of steam from said saturated steam valve, a second cylinder, apiston in said second cylinder connected to said superheated steamvalve, and a vented pipe connecting said cylinders.

5. In a boiler, a safety valve for saturated steam, a safetyvalve forsuperheated steam, a cylinder, means for supplying fluid under pressureto said cylinder, a piston in said cylinder operated by escape of steamfrom said saturated steam va1ve, a second cylinder, a piston in saidsecond cylinder connected to said superheated steam valve, and a pipeconnecting said cylinders.

6. In a boiler, a safety valve for saturated steam, a safety valve forsuperheated steam, a cylinder, a connection from the steam space of saidboiler to said cylinder, a piston in said cylinder operated by escape ofsteam from said saturated steam valve, a second cylinder, a piston invsaid second cylinder connected to said supercharge passage for openingsaid superheated steam safety valve.

CHARLES E. LUCKE.

August 29, 1933.

camps E. LUCKE.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: 'Page 1,lines 66, 68, 69 and 74, and page 2, lines 2 and 14, for "siphon" readsilphom'and that the said Letters Patent should be read with thesecorrections therein .that the same may conform to the record of the casein the Patent Office.-

Signed and sealed this 15th day-of May, A. D. 1934.

(Seal) 'Bryan Battey I

